Methods and devices for optimized cell acquisitions

ABSTRACT

Access terminals are adapted to blacklist one or more neighboring cells from acquisition attempts. For instance, an access terminal may receive a transmission including a list of neighboring cells to be monitored while connected to a particular serving cell. The access terminal may determine that a predefined number of consecutive acquisition attempts with a particular neighboring cell have failed. In response to failure of the predefined number of consecutive acquisition attempts, the access terminal can blacklist the neighboring cell from subsequent acquisition attempts for a predefined blacklisting period. Following the duration of the blacklisting period, the access terminal may conduct a subsequent acquisition attempt with the neighboring cell. Other aspects, embodiments, and features are also claimed and described.

CROSS REFERENCE TO RELATED APPLICATION & PRIORITY CLAIM

The present Application for Letters Patent claims priority to U.S.Provisional Application No. 61/653,341 entitled “METHODS AND DEVICES FOROPTIMIZING CELL ACQUISITIONS” filed May 30, 2012, and assigned to theassignee hereof and hereby expressly incorporated by reference herein asif fully set forth below and for all applicable purposes.

TECHNICAL FIELD

Embodiments of the present invention relate generally to wirelesscommunication, and more specifically to methods and devices forfacilitating optimized acquisitions of a cell and other communicationcomponents.

BACKGROUND

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be accessed byvarious types of access terminals adapted to facilitate wirelesscommunications, where multiple access terminals share the availablesystem resources (e.g., time, frequency, and power). Examples of suchwireless communications systems include code-division multiple access(CDMA) systems, time-division multiple access (TDMA) systems,frequency-division multiple access (FDMA) systems and orthogonalfrequency-division multiple access (OFDMA) systems.

Access terminals adapted to access one or more wireless communicationssystems are becoming increasingly popular, with consumers often usingpower-intensive applications that run on the access terminals. Accessterminals are typically battery-powered and the amount of power abattery can provide between charges is generally limited. There remainsa need for access terminal configured for and enabled to consume powerresources in an efficient manner.

BRIEF SUMMARY OF SOME EXAMPLES

Embodiments of the present invention are provisioned for addressing theabove discussed issues as well as others. Indeed, embodiments of thepresent invention provide wireless communication devises configured forefficient power consumption during operation. The following presents asimplified summary of one or more aspects of the present disclosure, inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated features of thedisclosure, and is intended neither to identify key or critical elementsof all aspects of the disclosure nor to delineate the scope of any orall aspects of the disclosure. Its sole purpose is to present someconcepts of one or more aspects of the disclosure in a simplified formas a prelude to the more detailed description that is presented later.

In some instances, features which may assist in extending the operatinglife of access terminals between recharging the battery can bebeneficial. Various features and aspects of the present disclosure areadapted to facilitate power conservation by optimizing cell acquisitionprocedures with one or more neighboring cells. According to at least oneaspect of the present disclosure, access terminals may include acommunications interface and a storage medium coupled with a processingcircuit. In some embodiments, the processing circuit may receive atransmission via the communications interface including a list of basestations to be monitored. In other embodiments, a processing circuit canfurther determine that a predefined number of consecutive acquisitionattempts with a base station have failed. In response to failure of thepredefined number of consecutive acquisition attempts, the processingcircuit may blacklist the base station from subsequent acquisitionattempts for a predefined blacklisting period of time. Following theexpiration of the blacklisting period, the processing circuit mayconduct a subsequent acquisition attempt with the base station.

Further aspects provide methods operational on an access terminalsand/or access terminals including means to perform such methods. One ormore examples of such methods may include determining that a predefinednumber of consecutive acquisition attempts with a base station havefailed. In response to failure of the predefined number of consecutiveacquisition attempts, subsequent acquisition attempts with the basestation may be ceased for a predefined blacklisting period. A subsequentacquisition attempt with the base station may be conducted following thepredefined blacklisting period.

Still further aspects include computer-readable mediums comprisingprogramming operational on an access terminal. According to one or moreexamples, such programming may be adapted for determining that apredefined number of consecutive acquisition attempts with a basestation have failed. The programming may further be adapted forblacklisting the base station from subsequent acquisition attempts for apredefined blacklisting period in response to failure of the predefinednumber of consecutive acquisition attempts. The programming can furtherbe adapted to conduct a subsequent acquisition attempt with the basestation following the duration of the blacklisting period.

Other aspects, embodiments, and features within the scope of the presentdisclosure will become apparent to those of ordinary skill in the artupon reviewing the following detailed description. Other aspects,features, and embodiments of the present invention will become apparentto those of ordinary skill in the art, upon reviewing the followingdescription of specific, exemplary embodiments of the present inventionin conjunction with the accompanying figures. While features of thepresent invention may be discussed relative to certain embodiments andfigures below, all embodiments of the present invention can include oneor more of the advantageous features discussed herein. In other words,while one or more embodiments may be discussed as having certainadvantageous features, one or more of such features may also be used inaccordance with the various embodiments of the invention discussedherein. In similar fashion, while exemplary embodiments may be discussedbelow as device, system, or method embodiments it should be understoodthat such exemplary embodiments can be implemented in various devices,systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a networkenvironment in which one or more aspects of the present disclosure mayfind application.

FIG. 2 is a block diagram illustrating select components of the wirelesscommunication system of FIG. 1 according to at least one example.

FIG. 3 is a flow diagram illustrating at least one example of a methodfor monitoring one or more neighboring cells according to someembodiments of the present invention.

FIG. 4 is a block diagram illustrating select components of an accessterminal according to at least one example.

FIG. 5 is a flow diagram illustrating at least one example of amodification to the method of FIG. 3 for monitoring one or moreneighboring cells according to some embodiments of the presentinvention.

FIG. 6 is a flow diagram illustrating a method operational on an accessterminal according to at least one example.

DETAILED DESCRIPTION

The description set forth below in connection with the appended drawingsis intended as a description of various configurations and is notintended to represent the only configurations in which the concepts andfeatures described herein may be practiced. The following descriptionincludes specific details for the purpose of providing a thoroughunderstanding of various concepts. However, it will be apparent to thoseskilled in the art that these concepts may be practiced without thesespecific details. In some instances, well known circuits, structures,techniques and components are shown in block diagram form to avoidobscuring the described concepts and features.

The various concepts presented throughout this disclosure may beimplemented across a broad variety of telecommunication systems, networkarchitectures, and communication standards. Certain aspects of thediscussions are described below for 3rd Generation Partnership Project(3GPP) protocols and systems, and related terminology may be found inmuch of the following description. However, those of ordinary skill inthe art will recognize that one or more aspects of the presentdisclosure may be employed and included in one or more other wirelesscommunication protocols and systems.

FIG. 1 is a block diagram of a network environment in which one or moreaspects of the present disclosure may find application. The wirelesscommunications system 100 includes base stations 102 adapted tocommunicate wirelessly with one or more access terminals 104. The system100 may support operation on multiple carriers (waveform signals ofdifferent frequencies). Multi-carrier transmitters can transmitmodulated signals simultaneously on the multiple carriers. Eachmodulated signal may be a CDMA signal, a TDMA signal, an OFDMA signal, aSingle Carrier Frequency Division Multiple Access (SC-FDMA) signal, etc.Each modulated signal may be sent on a different carrier and may carrycontrol information (e.g., pilot signals), overhead information, data,etc.

The base stations 102 can wirelessly communicate with the accessterminals 104 via a base station antenna. The base stations 102 may eachbe implemented generally as a device adapted to facilitate wirelessconnectivity (for one or more access terminals 104) to the wirelesscommunications system 100. The base stations 102 are configured tocommunicate with the access terminals 104 under the control of a basestation controller (see FIG. 2) via multiple carriers. Each of the basestation 102 sites can provide communication coverage for a respectivegeographic area. The coverage area 106 for each base station 102 here isidentified as cells 106-a, 106-b, or 106-c. The coverage area 106 for abase station 102 may be divided into sectors (not shown, but making uponly a portion of the coverage area). The system 100 may include basestations 102 of different types (e.g., macro, micro, femto and/or picobase stations).

One or more access terminals 104 may be dispersed throughout thecoverage areas 106. Each access terminal 104 may communicate with one ormore base stations 102. An access terminal 104 may generally include oneor more devices that communicate with one or more other devices throughwireless signals. Such an access terminal 104 may also be referred to bythose skilled in the art as a user equipment (UE), a mobile station(MS), a subscriber station, a mobile unit, a subscriber unit, a wirelessunit, a remote unit, a mobile device, a wireless device, a wirelesscommunications device, a remote device, a mobile subscriber station, amobile terminal, a wireless terminal, a remote terminal, a handset, aterminal, a user agent, a mobile client, a client, or some othersuitable terminology. An access terminal 104 may include a mobileterminal and/or an at least substantially fixed terminal. Examples of anaccess terminal 104 include a mobile phone, a pager, a wireless modem, apersonal digital assistant, a personal information manager (PIM), apersonal media player, a palmtop computer, a laptop computer, a tabletcomputer, a smartphone, a television, an appliance, an e-reader, adigital video recorder (DVR), a machine-to-machine (M2M) device, anentertainment device, and/or other communication/computing device whichcommunicates, at least partially, through a wireless or cellularnetwork.

Turning to FIG. 2, a block diagram illustrating select components of thewireless communication system 100 is depicted according to at least oneexample. As illustrated, the base stations 102 are included as at leasta part of a radio access network (RAN) 202. The radio access network(RAN) 202 is generally adapted to manage traffic and signaling betweenone or more access terminals 104 and one or more other network entities,such as network entities included in a core network 204. The radioaccess network 202 may, according to various implementations, bereferred to by those skill in the art as a base station subsystem (BSS),an access network, a GSM Edge Radio Access Network (GERAN), etc.

In addition to one or more base stations 102, the radio access network202 can include a base station controller (BSC) 206, which may also bereferred to by those of skill in the art as a radio network controller(RNC). The base station controller 206 is generally responsible for theestablishment, release, and maintenance of wireless connections withinone or more coverage areas associated with the one or more base stations102 which are connected to the base station controller 206. The basestation controller 206 can be communicatively coupled to one or morenodes or entities of the core network 204.

The core network 204 is a portion of the wireless communications system100 that provides various services to access terminals 104 that areconnected via the radio access network 202. The core network 204 mayinclude a circuit-switched (CS) domain and a packet-switched (PS)domain. Some examples of circuit-switched entities include a mobileswitching center (MSC) and visitor location register (VLR), identifiedas MSC/VLR 208, as well as a Gateway MSC (GMSC) 210. Some examples ofpacket-switched elements include a Serving GPRS Support Node (SGSN) 212and a Gateway GPRS Support Node (GGSN) 214. Other network entities maybe included, such as a EIR, HLR, VLR and AuC, some or all of which maybe shared by both the circuit-switched and packet-switched domains. Anaccess terminal 104 can obtain access to a public switched telephonenetwork (PSTN) 216 via the circuit-switched domain, and to an IP network218 via the packet-switched domain.

As an access terminal 104 operates within the wireless communicationssystem 100, the access terminal 104 may be connected with a servingcell, and may monitor one or more neighboring cells. In some examples,the access terminal 104 may monitor a predefined maximum number ofneighboring cells and may further rank the neighboring cells beingmonitored. As part of the process for monitoring the one or moreneighboring cells, the access terminal 104 typically ensures that it issynchronized with each neighboring cell. Turning to FIG. 3, a flowdiagram is shown illustrating an example of a method for monitoring theone or more neighboring cells (Ncells). As shown, the access terminal104 may initially acquire a neighboring cell, such as neighboring cell Aat 302. Acquisition may be accomplished by an acquisition procedure 303commonly referred to by those of skill in the art as a “combinedacquisition procedure.” During a combined acquisition procedure 303, theaccess terminal 104 may employ the control channel carrier associatedwith each cell to initially detect the Frequency Correction Channel(FCCH) for frequency synchronization, followed by the SynchronizationChannel (SCH) for time synchronization.

At 304, the access terminal 104 determines whether it has successfullycompleted frequency synchronization from the Frequency CorrectionChannel (FCCH). The Frequency Correction Channel (FCCH) is adownlink-only control channel in the GSM air interface. The FrequencyCorrection Channel (FCCH) may include a burst with a pre-definedsequence (e.g., an all-zero sequence) that produces a fixed tone in theGaussian minimum-shift keying (GMSK) modulator output. This tone enablesthe access terminal 104 to lock its local oscillator to the clock of thebase station 102 for frequency synchronization.

If the frequency synchronization was successful, the access terminal 104can synchronize to the neighboring cell's timing structures from theSynchronization Channel (SCH). At 306, the access terminal 104determines whether it has successfully decoded the SynchronizationChannel (SCH). The Synchronization Channel (SCH) typically follows inthe frame immediately after the Frequency Correction Channel (FCCH). TheSynchronization Channel (SCH) enables the access terminal 104 to quicklyidentify a nearby cell and synchronize to that cell's timing structures(e.g., TDMA structures). Each radio burst on the Synchronization Channel(SCH) may include the current frame clock of the particular base station102 associated with the cell, an identity code (e.g., base stationidentity code (BSIC)) associated with the base station 102, and anextended training sequence.

If both the frequency synchronization from the Frequency CorrectionChannel (FCCH) at 304 and the timing synchronization from theSynchronization Channel (SCH) at 306 are successful, the access terminal104 may perform periodic reconfirmations of the Synchronization Channel(SCH) as shown at 308 and 310. However, if either the frequencysynchronization at 304 or the timing synchronization at 306 fails, theaccess terminal 104 can move to step 312. At 312, the access terminal104 determines whether it is monitoring more than some predefined number‘N’ of neighboring cells. If the access terminal 104 is not monitoringmore than ‘N’ neighboring cells (e.g., it is monitoring ‘N’ or fewerneighboring cells), then the access terminal 104 may set a delay timerfor a predefined first delay period of x seconds at 314.

On the other hand, if the access terminal 104 is currently monitoringmore than ‘N’ neighboring cells, then the access terminal 104 determineswhether the particular neighboring cell which the access terminal 104failed to acquire (e.g., failed frequency or timing synchronizations) isranked as one of the top ‘M’ neighboring cells at 316, where ‘M’ is somepredefined number (e.g., top 2, top 3, top 4, etc.). If the neighboringcell is ranked as one of the top ‘M’ neighboring cells, then the accessterminal 104 can set the delay timer for the first delay period of xseconds at 314. If the neighboring cell is not ranked as one of the top‘M’ neighboring cells, then the access terminal 104 can set anotherdelay timer for a predefined second delay period of y seconds at 318,where the second delay period of y seconds is greater than the firstdelay period of x seconds. In some embodiments, the x and y periods canbe in a range of seconds or minutes (e.g., 10 seconds or 30 seconds).The x and y periods may also be dynamic and may also be configured to betied to a certain number of frames.

At 320, the access terminal 104 determines whether the particular delaytimer has expired (e.g., either the first delay period of x seconds orthe second delay period of y seconds). On expiration of whichever delaytimer was set, the access terminal 104 returns to the beginning at step302 to repeat the process of attempting to acquire the neighboring cell.

Typically, when the access terminal 104 is unable to acquire theneighboring cell, this process can continue to repeat after each firstor second delay period of x or y seconds. The delay periods can dependon which delay timer is initiated each consecutive attempt. According toa feature of the present disclosure, when an access terminal 104 isunable to acquire a cell after a predetermined number of consecutiveacquisition attempts, the particular cell can be ignored (e.g.,blacklisted) for a certain blacklisting period of time (e.g., 2 minutes,a certain number of frames, or other static/dynamic time periods) beforeattempting a subsequent acquisition. In some embodiments not focusing oncertain base stations can also include base stations that are undesired,not favored, cannot provide a certain desired service quality, and/ordisregarded in some embodiments. Such features may enable an accessterminal 104 to avoid devoting too much time trying to acquire a cellthat the access terminal 104 may be unable to acquire (e.g., as a resultof interference, low power, or other factors). By reducing continuedacquisition attempts, this can result in one or more of unnecessarypower drain, reduced performance loss, and improved user experience.

FIG. 4 is a block diagram illustrating select components of an accessterminal 400 according to at least one example. As shown, the accessterminal 400 may include a processing circuit 402 coupled to or placedin electrical communication with a communications interface 404 and astorage medium 406.

The processing circuit 402 is arranged to obtain, process and/or senddata, control data access and storage, issue commands, and control otherdesired operations. The processing circuit 402 may include circuitryadapted to implement desired programming provided by appropriate mediain at least one example. For example, the processing circuit 402 may beimplemented as one or more processors, one or more controllers, and/orother structure configured to execute executable programming. Examplesof the processing circuit 402 may include a general purpose processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic component, discrete gate or transistor logic,discrete hardware components, or any combination thereof designed toperform the functions described herein. A general purpose processor mayinclude a microprocessor, as well as any conventional processor,controller, microcontroller, or state machine. The processing circuit402 may also be implemented as a combination of computing components,such as a combination of a DSP and a microprocessor, a number ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, an ASIC and a microprocessor, or any other number of varyingconfigurations. These examples of the processing circuit 402 are forillustration and other suitable configurations within the scope of thepresent disclosure are also contemplated.

The processing circuit 402 is adapted for processing, including theexecution of programming, which may be stored on the storage medium 406.As used herein, the term “programming” shall be construed broadly toinclude without limitation instructions, instruction sets, data, code,code segments, program code, programs, subprograms, software modules,applications, software applications, software packages, routines,subroutines, objects, executables, threads of execution, procedures,functions, etc., whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise.

The communications interface 404 is configured to facilitate wirelesscommunications of the access terminal 400. For example, thecommunications interface 404 may include circuitry and/or programmingadapted to facilitate the communication of information bi-directionallywith respect to one or more network nodes. The communications interface404 may be coupled to one or more antennas (not shown), and includeswireless transceiver circuitry, including at least one receiver circuit408 (e.g., one or more receiver chains) and/or at least one transmittercircuit 410 (e.g., one or more transmitter chains).

The storage medium 406 may represent one or more computer-readable,machine-readable, and/or processor-readable devices for storingprogramming, such as processor executable code or instructions (e.g.,software, firmware), electronic data, databases, or other digitalinformation. The storage medium 406 may also be used for storing datathat is manipulated by the processing circuit 402 when executingprogramming The storage medium 406 may be any available media that canbe accessed by a general purpose or special purpose processor, includingportable or fixed storage devices, optical storage devices, and variousother mediums capable of storing, containing and/or carrying programmingBy way of example and not limitation, the storage medium 406 may includea computer-readable, machine-readable, and/or processor-readable storagemedium such as a magnetic storage device (e.g., hard disk, floppy disk,magnetic strip), an optical storage medium (e.g., compact disk (CD),digital versatile disk (DVD)), a smart card, a flash memory device(e.g., card, stick, key drive), random access memory (RAM), read onlymemory (ROM), programmable ROM (PROM), erasable PROM (EPROM),electrically erasable PROM (EEPROM), a register, a removable disk,and/or other mediums for storing programming, as well as any combinationthereof.

The storage medium 406 may be coupled to the processing circuit 402 suchthat the processing circuit 402 can read information from, and writeinformation to, the storage medium 406. That is, the storage medium 406can be coupled to the processing circuit 402 so that the storage medium406 is at least accessible by the processing circuit 402, includingexamples where the storage medium 406 is integral to the processingcircuit 402 and/or examples where the storage medium 406 is separatefrom the processing circuit 402 (e.g., resident in the access terminal400, external to the access terminal 400, and/or distributed acrossmultiple entities).

Programming stored by the storage medium 406, when executed by theprocessing circuit 402, causes the processing circuit 402 to perform oneor more of the various functions and/or process steps described herein.For example, the storage medium 406 may include cell acquisitionoperations 414. The cell acquisition operations 414 can be implementedby the processing circuit 402 to perform acquisition of a cell,including employing a blacklisting delay period between acquisitionattempts following a predetermined number of consecutive failedacquisition attempts. Thus, according to one or more aspects of thepresent disclosure, the processing circuit 402 is adapted to perform (inconjunction with the storage medium 406) any or all of the processes,functions, steps and/or routines for any or all of the access terminalsdescribed herein (e.g., access terminal 104 and/or 400). As used herein,the term “adapted” in relation to the processing circuit 402 may referto the processing circuit 402 being one or more of configured, employed,implemented, and/or programmed to perform a particular process,function, step and/or routine according to various features describedherein.

In operation, the access terminal 400 can wait a predetermined period oftime before attempting to acquire a neighboring cell after apredetermined number of consecutive acquisition attempts have failed.For example, FIG. 5 shows a flow diagram including aspects that may beimplemented within the flow diagram of FIG. 3. Such aspects can beimplemented after failure of the frequency synchronization at 304 or thetiming synchronization at 306 in FIG. 3, and before attempting toacquire the neighboring cell at 302 for a subsequent time. In theexample depicted in FIG. 5, the additional steps may occur afterdetermining whether the number of neighboring cells is greater than thepredefined number ‘N’ at 312. For example, when either the frequencysynchronization at 304 fails or the timing synchronization at 306 fails,the access terminal can determine at 312 whether it is monitoring morethan some predefined number ‘N’ of neighboring cells. If the accessterminal 400 is not monitoring more than ‘N’ neighboring cells (e.g., itis monitoring ‘N’ or fewer neighboring cells), then the access terminal400 may move to step 314 in FIG. 3, where a delay timer is set for apredefined first delay period of x seconds.

On the other hand, when the number of neighboring cells is greater thanthe predefined number ‘N’, the access terminal 400 can determine at step502 whether the acquisition procedure for the neighboring cell hasfailed a predefined number of times consecutively. For instance, in someexamples the predefined number of consecutive failures may be two.Accordingly, if the access terminal 400 has failed to acquire theneighboring cell two consecutive times, the access terminal candetermine at step 502 that the number of consecutive failures is equalto the predefined value of two.

If the number of consecutive failures to acquire the neighboring cell isstill less than the predefined number, the access terminal 400 can go tostep 316 of FIG. 3 and continue onward from 316, as described above withreference to FIG. 3. When the number of consecutive failures to acquirethe neighboring cell is equal to the predefined number, the accessterminal 400 can blacklist the particular neighboring cell. This meansthat the access terminal 400 sets a timer for a predefined blacklistingperiod of z seconds (e.g., the z timer) and waits for at least theduration of this blacklisting period at 504 before another attempt atacquiring the neighboring cell is performed. In some examples, theblacklisting period is substantially larger than the first and seconddelay periods. That is, the blacklisting period of z seconds issubstantially larger than the first delay period of x seconds and thesecond delay period of y seconds (e.g., z>>x and z>>y) for the for thefirst and second delay periods described above. In some instances, theaccess terminal 400 may employ one of the first or second delay periodsdescribed above after the duration of the blacklisting period. In suchexamples, the access terminal 400 can move to the step 314 of FIG. 3after the blacklisting period, and continue onward as described above.In other examples, the access terminal 400 may attempt anotheracquisition procedure 303 after the duration of the z timer (e.g., theblacklisting period) at 504, as indicated by the broken arrow 506.

Additional aspects of the present disclosure include methods ofoperation for an access terminal. FIG. 6 is a flow diagram illustratingan example of a method operational on an access terminal, such as theaccess terminal 400, according to at least one implementation. Referringto FIGS. 4 and 6, an access terminal 400 may initially receive atransmission from the network including a list of neighboring cells (orbase stations) to be monitored by the access terminal 400 at step 602.For example, each time the access terminal 400 connects to a servingcell, the processing circuit 402 may receive a transmission via thecommunications interface 404 including a list of neighboring cells whichthe access terminal 400 is to monitor. To facilitate such monitoring,the access terminal 400 may maintain synchronization with at least someof the neighboring cells from the received list.

At step 604, the access terminal can conduct an acquisition attempt witha neighboring cell included in the received list. The acquisitionattempt can facilitate synchronization with the neighboring cell. Theinitial acquisition attempt of a neighboring cell can be conductedwithout any delay. Such an acquisition attempt may be conducted by theprocessing circuit 402 executing the cell acquisition operations 412 toperform a combined acquisition procedure. As noted above, a combinedacquisition procedure may include the processing circuit 402 detectingvia the communications interface 404 a Frequency Correction Channel(FCCH) for frequency synchronization, followed by a SynchronizationChannel (SCH) for time synchronization.

At step 606, the access terminal 400 may determine that the acquisitionattempt failed. For example, the processing circuit 402 executing thecell acquisition operations 412 may determine that the acquisitionattempt failed. In at least one example, the processing circuit 402executing the cell acquisition operations 412 may determine that eitherthe frequency synchronization or the timing synchronization of acombined acquisition procedure has failed. Other factors may also beutilized to determine that acquisition has failed. For example,transmission power, service quality, and network load may also beconsidered in alternative embodiments.

At step 608, the access terminal 400 can determine whether a predefinednumber of consecutive failures have occurred. For example, theprocessing circuit 402 executing the cell acquisition operations 412 maykeep a count of the number of consecutive access attempts that have beenmade for each cell. When the count number is below a predeterminedvalue, the processing circuit 402 executing the cell acquisitionoperations 412 can determine that the predetermined number ofconsecutive failures have not occurred. On the other hand, when thecount number is equal to the predetermined value, the processing circuit402 executing the cell acquisition operations 412 can determine that thepredetermined number of consecutive failures have occurred.

When the access terminal 400 determines that the predetermined number ofconsecutive failures have not occurred, the access terminal 400 canreturn to step 604, in which a subsequent access attempt is conductedafter waiting for a duration of a predefined delay period. For instance,the processing circuit 402 can determine that the predetermined numberof consecutive failures have not occurred. As a result, the processingcircuit 402 executing the cell acquisition operations 412 initiate asubsequent access attempt at step 604 after the processing circuit 402has waited for the duration of a predefined delay period. The delayperiod may vary according to the cell ranking and/or the total number ofcells being monitored. For instance, the processing circuit 402executing the cell acquisition operations 412 may wait a first delayperiod of x seconds when a number of monitored neighboring cells is lessthan or equal to a predetermined threshold, or when the neighboring cellis ranked in a predefined number of top neighboring cells (see, e.g.,steps 312, 314, 316, and 320 in FIG. 3 and the associated descriptionabove). The processing circuit 402 executing the cell acquisitionoperations 412 may wait a longer second delay period of y seconds whenthe number of monitored neighboring cells is greater than thepredetermined threshold, and the neighboring cell is not ranked in thepredefined number of top neighboring cells (see, e.g., steps 312, 316,318 and 320 in FIG. 3 and the associated description above).

When the access terminal 400 determines that the predetermined number ofconsecutive failures have occurred at step 608, the access terminal 400can wait for the duration of a predefined blacklisting period (e.g.,time z) at step 610 before attempting to reacquire the cell (e.g., theblacklisted cell). That is, the access terminal 400 can cease fromsubsequent acquisition attempts with the neighbor cell for a predefinedblacklisting period. For example, in response to the failure of thepredefined number of consecutive acquisition attempts, the processingcircuit 402 executing the cell acquisition operations 412 can blacklistthe neighboring cell for the duration of the predefined blacklistingperiod of z seconds. After the blacklisting period has expired, theprocessing circuit 402 executing the cell acquisition operations 412 canconduct a subsequent acquisition attempt. The amount of time for theblacklisting period (e.g., time z) can be selected to be substantiallylarger than amount of times associated with the first and second delayperiods (e.g., z>>x and z>>y).

In at least some instances, the blacklisting period (e.g., time z) canbe varied depending on the number of neighbor cells being monitoredand/or the number of consecutive times a neighboring cell has beenblacklisted. The processing circuit 402 executing the cell acquisitionoperations 412 may avoid blacklisting a cell if the number of cellsbeing monitored are less than ‘N’. In such cases, the processing circuitexecuting the cell acquisition operations 412 may employ the first orsecond delay period instead of the blacklisting period. Avoidingblacklisting of a cell in such cases can reduce the possibility of theaccess terminal 400 going out of service as a result of all the neighborcells being blacklisted. In some examples, the processing circuit 402executing the cell acquisition operations 412 may skip the predefinedwaiting period of step 610 if the total number of all neighboring cellsis below some threshold (e.g. there are fewer than ‘N’ neighbor cells).By way of example and not limitation, some implementations may employ athreshold of six (6) neighboring cells. In such examples, when there arefewer than six (6) neighboring cells in the received list, theprocessing circuit 402 executing the cell acquisition operations 412 canskip step 610 and go directly to step 604.

One or more of the various features and aspects of the presentdisclosure can enable access terminals to, other things, avoid devotingan excessive amount of time attempting to acquire a neighboring cellthat the access terminal may be at least temporarily unable to acquire.By reducing the number of acquisition attempts by the access terminal,significant power savings, improvements in performance and otheradvantages can be achieved.

While the above discussed aspects, arrangements, and embodiments arediscussed with specific details and particularity, one or more of thecomponents, steps, features and/or functions illustrated in FIGS. 1, 2,3, 4, 5 and/or 6 may be rearranged and/or combined into a singlecomponent, step, feature or function or embodied in several components,steps, or functions. Additional elements, components, steps, and/orfunctions may also be added or not utilized without departing from theinvention. The apparatus, devices and/or components illustrated in FIGS.1, 2 and/or 4 may be configured to perform or employ one or more of themethods, features, parameters, or steps described in FIGS. 3, 5 and/or6. The novel algorithms described herein may also be efficientlyimplemented in software and/or embedded in hardware.

Also, it is noted that at least some implementations have been describedas a process that is depicted as a flowchart, a flow diagram, astructure diagram, or a block diagram. Although a flowchart may describethe operations as a sequential process, many of the operations can beperformed in parallel or concurrently. In addition, the order of theoperations may be re-arranged. A process is terminated when itsoperations are completed. A process may correspond to a method, afunction, a procedure, a subroutine, a subprogram, etc. When a processcorresponds to a function, its termination corresponds to a return ofthe function to the calling function or the main function. The variousmethods described herein may be partially or fully implemented byprogramming (e.g., instructions and/or data) that may be stored in amachine-readable, computer-readable, and/or processor-readable storagemedium, and executed by one or more processors, machines and/or devices.

Those of skill in the art would further appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the embodiments disclosed herein may beimplemented as hardware, software, firmware, middleware, microcode, orany combination thereof. To clearly illustrate this interchangeability,various illustrative components, blocks, modules, circuits, and stepshave been described above generally in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system.

The various features associate with the examples described herein andshown in the accompanying drawings can be implemented in differentexamples and implementations without departing from the scope of thepresent disclosure. Therefore, although certain specific constructionsand arrangements have been described and shown in the accompanyingdrawings, such embodiments are merely illustrative and not restrictiveof the scope of the disclosure, since various other additions andmodifications to, and deletions from, the described embodiments will beapparent to one of ordinary skill in the art. Thus, the scope of thedisclosure is only determined by the literal language, and legalequivalents, of the claims which follow.

What is claimed is:
 1. An access terminal, comprising: a communicationsinterface; a storage medium; and a processing circuit coupled to thecommunications interface and the storage medium, the processing circuitadapted to: receive a transmission via the communications interfaceincluding a list of base stations to be monitored; determine that apredefined number of consecutive acquisition attempts with a basestation have failed; blacklist the base station from subsequentacquisition attempts for a predefined blacklisting period in response tofailure of the predefined number of consecutive acquisition attempts;and conduct a subsequent acquisition attempt with the base stationfollowing the duration of the blacklisting period.
 2. The accessterminal of claim 1, wherein the processing circuit is adapted to: waitfor a duration of a delay period between each of the predefined numberof consecutive acquisition attempts, wherein the delay period is shorterthan the blacklisting period.
 3. The access terminal of claim 2, whereinthe processing circuit is adapted to: wait for a first delay period whena number of base stations in the received list is less than or equal toa predetermined threshold, or when the base station is ranked in apredefined number of top base stations; and wait for a second delayperiod that is greater than the first delay period when the number ofbase stations in the received list is greater than the predeterminedthreshold, and the base station is not ranked in the predefined numberof top base stations.
 4. The access terminal of claim 1, wherein theprocessing circuit is further adapted to: blacklist the base stationfrom subsequent acquisition attempts for a predefined blacklistingperiod when a number of base stations in the received list is less thanor equal to a predetermined threshold.
 5. The access terminal of claim1, wherein the processing circuit is further adapted to: blacklist thebase station from subsequent acquisition attempts for a predefinedblacklisting period when a number of other base stations currentlyblacklisted is below a predetermined threshold.
 6. The access terminalof claim 1, wherein the processing circuit is further adapted to:conduct the subsequent acquisition attempt with the base station after adelay period based on a ranking of the base station.
 7. The accessterminal of claim 1, wherein the predefined number of consecutiveacquisition attempts and the subsequent acquisition attempt eachcomprises a combined acquisition procedure.
 8. A method operational onan access terminal, comprising: determining that a predefined number ofconsecutive acquisition attempts with a base station have failed;ceasing from subsequent acquisition attempts with the base station for apredefined blacklisting period in response to failure of the predefinednumber of consecutive acquisition attempts; and conducting a subsequentacquisition attempt with the base station following the predefinedblacklisting period.
 9. The method of claim 8, further comprising:receiving a transmission including a list of base stations to bemonitored, wherein the base station is included in the received list.10. The method of claim 8, further comprising: conducting the predefinednumber of consecutive acquisition attempts with the base station; andwaiting for a duration of a delay period between conducting each of thepredefined number of consecutive acquisition attempts, wherein the delayperiod is shorter than the blacklisting period.
 11. The method of claim10, wherein waiting for the duration of the delay period between each ofthe predefined number of consecutive acquisition attempts comprises:waiting for a first delay period when a number of monitored basestations is less than or equal to a predetermined threshold, or when thebase station is ranked in a predefined number of top base stations; andwaiting for a second delay period that is greater than the first delayperiod when the number of monitored base stations is greater than thepredetermined threshold, and the base station is not ranked in thepredefined number of top base stations.
 12. The method of claim 8,wherein ceasing from subsequent acquisition attempts with the basestation for a predefined blacklisting period in response to failure ofthe predefined number of consecutive acquisition attempts furthercomprises: ceasing from subsequent acquisition attempts with the basestation for a predefined blacklisting period in response to failure ofthe predefined number of consecutive acquisition attempts, and furtherin response to an availability of a predefined number of other basestations for acquisition by the access terminal.
 13. The method of claim8, wherein ceasing from subsequent acquisition attempts with the basestation for a predefined blacklisting period in response to failure ofthe predefined number of consecutive acquisition attempts furthercomprises: ceasing from subsequent acquisition attempts with the basestation for a predefined blacklisting period in response to failure ofthe predefined number of consecutive acquisition attempts, and furtherin response to a number of other blacklisted base stations being below apredefined threshold.
 14. An access terminal, comprising: means fordetermining that a predefined number of consecutive acquisition attemptswith a base station have failed; means for ceasing from subsequentacquisition attempts with the base station for a predefined blacklistingperiod in response to failure of the predefined number of consecutiveacquisition attempts; and means for conducting a subsequent acquisitionattempt with the base station following the predefined blacklistingperiod.
 15. The access terminal of claim 14, further comprising: meansfor performing the predefined number of consecutive acquisition attemptswith the base station; and means for waiting for a duration of a delayperiod between each of the predefined number of consecutive acquisitionattempts, wherein the delay period is shorter than the blacklistingperiod.
 16. The access terminal of claim 15, wherein the delay period isselected from at least two delay periods, including a first delay periodand a second delay period that is longer than the first delay period,and further comprising: means for selecting the first delay period whena total number of monitored base stations is less than or equal to apredetermined threshold, or when the base station is ranked in apredefined number of top base stations; and means for selecting thesecond delay period when the total number of monitored base stations isgreater than the predetermined threshold, and the base station is notranked in the predefined number of top base stations.
 17. The accessterminal of claim 14, wherein an acquisition attempt comprises acombined acquisition procedure.
 18. A computer-readable medium,comprising programming for: determining that a predefined number ofconsecutive acquisition attempts with a base station have failed;blacklisting the base station from subsequent acquisition attempts for apredefined blacklisting period in response to failure of the predefinednumber of consecutive acquisition attempts; and conducting a subsequentacquisition attempt with the base station following the duration of theblacklisting period.
 19. The computer-readable medium of claim 18,further comprising programming for: receiving a transmission including alist of base stations to be monitored, wherein the base station isincluded in the received list.
 20. The computer-readable medium of claim18, further comprising programming for: conducting the predefined numberof consecutive acquisition attempts with the base station; and waitingfor a duration of a delay period between conducting each of thepredefined number of consecutive acquisition attempts, wherein the delayperiod is shorter than the blacklisting period.
 21. Thecomputer-readable medium of claim 20, wherein waiting for the durationof the delay period between each of the predefined number of consecutiveacquisition attempts comprises: waiting for a first delay period when anumber of monitored base stations is less than or equal to apredetermined threshold, or when the base station is ranked in apredefined number of top base stations; and waiting for a second delayperiod that is greater than the first delay period when the number ofmonitored base stations is greater than the predetermined threshold, andthe base station is not ranked in the predefined number of top basestations.
 22. The computer-readable medium of claim 18, furthercomprising programming for: blacklisting the base station fromsubsequent acquisition attempts for a predefined blacklisting period inresponse to failure of the predefined number of consecutive acquisitionattempts, and further in response to an availability of a predefinednumber of other base stations for acquisition.
 23. The computer-readablemedium of claim 18, further comprising programming for: blacklisting thebase station from subsequent acquisition attempts for a predefinedblacklisting period in response to failure of the predefined number ofconsecutive acquisition attempts, and further in response to a number ofother blacklisted base stations being below a predefined threshold. 24.A device capable of communicating wirelessly with another device, thedevice comprising: a communications interface operatively coupled to aprocessor such that processor is configured to manage wirelesscommunications via the communications interface; the process beingfurther configured to determine that a predefined number of consecutiveacquisition attempts with at least one base station have failed; ignorethe at least one base station from subsequent acquisition attempts for apredefined blacklisting period; and conduct a subsequent acquisitionattempt with the at least one base station following the duration of theblacklisting period.
 25. The device of claim 24, wherein the processoris configured to receive a transmission via the communications interfaceincluding a list of base stations to be monitored.